1. Field of the Invention
This invention relates to a signal amplifier for a signal recording device with magnetic deflection. In particular this invention relates to a vertical or y-amplifier for the vertical deflection coil of a magnetically deflecting oscilloscope. Still more particularly, this invention relates to a signal amplifier for medical technology, where, as signals of interest, signals representing a patient's physiological parameters are amplified, processed and displayed.
By the term "signal recording device with magnetic deflection" there are to be understood magnetically deflecting oscilloscopes in the broadest sense, but also printing devices with a magnetically deflected stylus or printing jet, such as rapid ink jet printers with magnetically deflectable nozzle for the ink jet. Such signal recording devices always have at least one deflection coil, which is controlled by an amplified driving or measuring signal.
2. Description of the Prior Art
Signal amplifiers of the above described kind must often process signals which contain a great variety of frequencies. In the field of electro-medicine, for instance, the main physiological parameters of a patient, as in particular blood pressure, respiration, EKG signals etc., comprise frequencies in the range between 0 and 100 Hz. If, however, extraordinary circumstances prevail, such as certain forms of arhythmia in the EKG, or if stimulation pulses are superposed on the input signal, as in particular pacemaker pulses in the EKG, the frequency range of the input signals will extend to still higher values, e.g. as high as 300 Hz or more. Generally, high frequencies mean high signal amplitudes. If it is desired that such high signal amplitudes are to be reproduced on the signal recording device largely undistorted, the signal amplifier must be designed for as wide as possible a control range. Design for a wide control range, however, will increase the power requirement of the amplifier, since high signal amplitudes require high deflection currents in the deflection coil.